Transient Astigmatism

Hi all,

I need some advice/guidance. I didn’t have much luck on the Facebook group, so trying my luck here.

I am not looking for diopter-specific advice but trying to understand which would be a better route in my situation.

Here is my prescription history.

January 2019
OD (Right eye) -0.75 CYL -0.50 Axis 130
OS (Left eye) -1.00

December 2020
OD (Right eye) -0.50 CYL -0.50 Axis 105
OS (Left eye) -0.75 CYL -0.50 Axis 180

As you can see I was able to improve my vision by a quarter diopter in each eye. But my left eye now has astigmatism in it. Jake just released a video talking about Transient astigmatism with low diopter which I think I am probably going through at the moment.

For the last year, I have been in the process of equalizing my prescription and it has been a slow journey due to a lower diopter. I am currently wearing (OS/OD -0.50) without any cylinder value.

So I have two questions:

  1. Do you think I should keep trying to equalize both of my eyes? Or go back to reducing my diopter for an individual eye?
  2. Does it make sense to just stay at my current glasses till transient astigmatism clears up? Or make adjustments to the diopter/CYL?

Any advice or guidance would be greatly appreciated.

Best,
Saif

Do not correct for transient astigmatism at all.

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So you think the best option for me is to stick to my current glasses? OS/OD -0.50 (no cyl) till it clears itself out?

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No cylinder, definitely. If you feel -0.50 is too weak for your left eye, you might want to increase spherical, to avoid blur adaptation and/or halt of weaker eye.

If you have astigmatism that is not transient, you can just go reducing spherical again or go for equalizing.

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And he says: stick with it for a couple of months if the challenge level is OK (you hardly notice it) or step back if it is very noticeable.
So stick with the -0.5 no cyl or step back or rather step up to -0.75 no cyl. This is my interpretation.
You’re equalising as well as dropping cyl and reducing the sph so that can push the 3 months out to 3 times longer and it’s still normal especially as you are in the last diopter.

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It does seem like -0.50 is too weak for the left eye. The blur is more noticeable when I cover up my right eye since it feels like the right eye is doing most of the work. But, I can clear the image out. Now I wonder if I should leave my right eye at -0.50 (no cyl) or drop it down to -0.25 (no cyl) so this eye has the chance to improve rather than just waiting for the left eye to catch up. That means I will not be equalizing. Which approach do you think makes more sense?

  1. Step up the left eye to -0.75 (no cyl) and keep the right eye at -0.50 (no cyl)
  2. Step up the left eye to -0.75 (no cyl) and drop the right eye at -0.25 (no cyl)
  3. Stick to my current glasses -0.50 (no cyl) for maybe three more months and see if anything changes or not. (With summer around the corner, the goal is to spend more time outside)

Don’t drop from the right eye. I’d go back as you describe in option 1, or would even consider -0.75D no cyl for both eyes. It depends on how much your brain got used to the same correction by now. One of them should be able to nudge the left eye. Once you managed to activate the left eye (by wearing stronger corrections for a week or a few weeks), you can gradually reintroduce the -0.5D no cyl both eyes. By gradually I mean e.g. first wearing them on a nice sunny day, then at daylight, and step back to relax when you feel that the left eye needs a bit of a rest.

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Okay, so I tried to use -0.75 (no cyl) in both eyes and, the right eye feels like it is overcorrected. It felt like the objects are zoomed in. Maybe I need to get used to it since I have been at -0.50 (no cyl) for a while or, do you think I should leave the right eye at -0.50 (no cyl) and bring the left eye at -0.75 (no cyl)?

The last diopter has both pros and cons.
-1.00D = 89 to 113.9cm
-0.75D = 114 to 159cm
-0.50D = 160 to 266cm
-0.25D = 267 to 800cm

You should be OK with both eyes up to at least 150 cms. But it might be that your left eye is still around 160 cms while the right one is at about 250 cms already. Maybe on an exhausting day with lots of stress and crappy lights both eyes drop about 10 or 20 cms, so your left eye drops back to 140 or 150 cms (which is -0.75D again) and the right eye drops to 230 or 240 cms (which is still at the better end of -0.5D). That’s a huge difference. Working that away will require patience.
For encouragement, this was my dance around bringing the eyes to the same correction. I got stuck at -0.75D and -0.5D, too. And actually, based on my mini statistics this is quite common.

So which glasses to step back to?
I’m afraid it is something that you’ll need to figure out.
If your brain is OK with the equal correction in both eyes, i.e. got used to it by now but has just a bit too much blur in general to clear then the -0.75D / -0.75D will feel better.
If your brain is OK with the reduction but is still working on the equalisation then the right -0.5D / left -0.75D will feel better.

So find out which one it is: is it too much blur in general? or is it the brain requesting stronger correction for the left eye only? and use that pair as the ‘stronger’ pair to encourage the left eye to join into the party.
Once you have the pair that gives you a bit of break from too much struggle, you can start reintroducing the -0.5D / -0.5D when it feels OK.

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I feel like transient astigmatism is the result of trying to do a large reduction or excessive undercorrection (which seems to be the case when jumping from -1.5 or even -1 directly to 0), since reducing too quickly even at higher diopters (around -2 to -1.5) seems to have resulted in transient astigmatism for me, and someone who used +2.5 lens seemed to develop transient-astigmatism-like ghosting, which was used as an example in a warning about using plus lens carefully.

Here’s an example of what can go wrong:

[…]

I attribute the severe ghosting/triple vision to very aggressive use of plus glasses for the first year or so. I was wearing +2.5 readers for up to 12 hours a day. Even looking into the distance with them. I wonder if I have permanently damaged my eyes?

This ghosting is making daily life increasingly difficult and I fear for my future quality of life if the double/triple/quadruple vision is not shaken off.

I attach pictures to give you an idea of what I see

[the picture in the article looks like astigmatic double vision]

If you’re up on the endmyopia ways, you might see this and think, ah, astigmatic / directional blur. Some astigmatism correction will fix that.

Which would be correct.

But this is the problem. You can end up creating the need for more complex focal plane correction by aggressively introducing focal plane changes trying to correct your myopia. The shortcut becomes the long way home.

Maybe transient astigmatism is real astigmatism, but you don’t want to add cylinder (unless you seriously mess up and let it get too bad) because it happened between spherical reductions and you know you’ll clear it when the spherical reduction is over.


Shouldn’t this note about equalizing apply to everyone, including high myopes with normalized? In the world of optics, everything is in diopters, so the diopter fluctuation should be similar, resulting in different cm changes.

For example, if the eyes are -0.6/-0.4 (167 cm, 250 cm), and they experience a -0.1 change from stress, then they become -0.7/-0.5 (143 cm, 200 cm), so while one eye lost 24 cm, the other lost 50 cm. Even though both eyes “round to” -0.5, there is still a 0.2 D gap to be equalized.

For higher myopes, shouldn’t this be the same when they are wearing normalized? A -10.6/-10.4 myope should get the exact same effect with -10 normalized.